One of the teenage boys who was shot dead in south London was killed with a Mac 10 machine gun, known as the spray and pray, which shoots more than a thousand rounds a minute, police said yesterday. Michael Dosunmu, 15, was in bed at home in Peckham when two gunmen burst into his room and sprayed him with bullets. He died of multiple gunshot wounds. Police said yesterday they have identified the weapon used as a Mac 10, a favourite of Yardie style gangsters, which can fire 1,200 rounds a minute.

Michael, a churchgoing schoolboy, was killed in the second of a series of murders of young black men in south London last month. Detective Superintendent Gary Richardson, who is leading the investigation into his killing, said yesterday: "This was a dreadful murder. Someone must have information about this weapon and we appeal to them to contact us."

In an interview with the BBC's Crimewatch last night Michael's sister, Shakira, told how she fought to for several minutes to save his life. She said: "I did CPR [cardio-pulmonary resuscitation] for him ... I was just screaming. I said 'Michael, you can't leave me like this'."

Her brother was taken to King's College Hospital where he died an hour later. Michael, who had turned 15 two days earlier, was one of three south London teenagers shot dead in less than a fortnight last month. His mother, also called Shakira, said: "I don't think there is any other pain that is more painful than this ..." Michael's father, Rasak, said his wife was visiting Nigeria when the shooting took place and he did not tell her Michael was dead until she returned. He said: "I was so worried about how my wife would take the killing. So I phoned and said that Michael was seriously sick and she needed to come back. What goes around will turn around one day. It might be Michael today, it might be their own family tomorrow." Police believe the shooting may have been a case of mistaken identity, linked to a fatal stabbing of a 21-year-old in an adjacent road three days before. His family described him as a "peace-loving boy", a regular churchgoer who was honest and not involved in any local gangs.

The shooting, on February 6, was the second in which schoolboys died.

James Andre Smartt-Ford, 16, of New Malden, was shot in front of hundreds of people at an ice rink in Streatham. Days later Billy Cox, 15, was shot dead at his home in south-west London. Two men and three youths have been arrested over Michael Dosunmu's murder and released on bail.